package edu.cicese.alz.swing;

import javax.swing.Action;
import javax.swing.JTable;
import javax.swing.SwingUtilities;
import java.awt.event.ActionEvent;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;


/*
 *  This class listens for changes made to the data in the table via the
 *  TableCellEditor. When editing is started, the value of the cell is saved
 *  When editing is stopped the new value is saved. When the oold and new
 *  values are different, then the provided Action is invoked.
 *
 *  The source of the Action is a TableCellListener instance.
 */
public class TableCellListener implements PropertyChangeListener, Runnable {
	private JTable table;
	private Action action;

	private int row;
	private int column;
	private Object oldValue;
	private Object newValue;

	/**
	 * Create a TableCellListener.
	 *
	 * @param table  the table to be monitored for data changes
	 * @param action the Action to invoke when cell data is changed
	 */
	public TableCellListener(JTable table, Action action) {
		this.table = table;
		this.action = action;

		this.table.addPropertyChangeListener(this);
	}

	/**
	 * Create a TableCellListener with a copy of all the data relevant to
	 * the change of data for a given cell.
	 *
	 * @param row      the row of the changed cell
	 * @param column   the column of the changed cell
	 * @param oldValue the old data of the changed cell
	 * @param newValue the new data of the changed cell
	 */
	private TableCellListener(JTable table, int row, int column, Object oldValue, Object newValue) {
		this.table = table;
		this.row = row;
		this.column = column;
		this.oldValue = oldValue;
		this.newValue = newValue;
	}

	/**
	 * Get the column that was last edited.
	 *
	 * @return the column that was edited
	 */
	public int getColumn() {
		return column;
	}

	/**
	 * Get the new value in the cell.
	 *
	 * @return the new value in the cell
	 */
	public Object getNewValue() {
		return newValue;
	}

	/**
	 * Get the old value of the cell.
	 *
	 * @return the old value of the cell
	 */
	public Object getOldValue() {
		return oldValue;
	}

	/**
	 * Get the row that was last edited.
	 *
	 * @return the row that was edited
	 */
	public int getRow() {
		return row;
	}

	/**
	 * Get the table of the cell that was changed.
	 *
	 * @return the table of the cell that was changed
	 */
	public JTable getTable() {
		return table;
	}

	//
//  Implement the PropertyChangeListener interface
//
	public void propertyChange(PropertyChangeEvent e) {
		//  A cell has started/stopped editing

		if ("tableCellEditor".equals(e.getPropertyName())) {
			if (table.isEditing()) {
				processEditingStarted();
			} else {
				processEditingStopped();
			}
		}
	}

	/*
	 *  Save information of the cell about to be edited
	 */
	private void processEditingStarted() {
		//  The invokeLater is necessary because the editing row and editing
		//  column of the table have not been set when the "tableCellEditor"
		//  PropertyChangeEvent is fired.
		//  This results in the "run" method being invoked

		SwingUtilities.invokeLater(this);
	}

	/*
		 *  See above.
		 */
	public void run() {
//		row = table.convertRowIndexToModel(table.getEditingRow());
		row = table.getEditingRow();

		column = table.convertColumnIndexToModel(table.getEditingColumn());

		oldValue = table.getModel().getValueAt(row, column);
		newValue = null;
	}

	/*
	 *	Update the Cell history when necessary
	 */
	private void processEditingStopped() {
		newValue = table.getModel().getValueAt(row, column);

		//  The data has changed, invoke the supplied Action

		if (column != 5 && !newValue.equals(oldValue)) {
			//  Make a copy of the data in case another cell starts editing
			//  while processing this change

			TableCellListener tcl = new TableCellListener(
					getTable(), getRow(), getColumn(), getOldValue(), getNewValue());

			ActionEvent event = new ActionEvent(
					tcl,
					ActionEvent.ACTION_PERFORMED,
					"");
			action.actionPerformed(event);
		}
	}
}